1. Field of the Invention
This invention relates to blister packaging of products such as medication in pill, tablet, capsule or lozenge form, and more particularly to an improved, child resistant blister package for such products.
2. Description of the Prior Art
It is common practice to use blister packages to package small solid articles or products which may be dispensed from the package by applying pressure to the blister to force the article or product from an individual blister or capsule through a rupturable foil. Since such packaging is widely used in the marketing of medicaments in pill, tablet, capsule or lozenge form (hereinafter, pills) the invention will be referred to herein with respect to package particularly suitable for such use, it being understood that the package maybe used for other products as well.
Blister packages of the type employed for packaging medication in pill form typically comprise a first sheet of transparent or translucent thermoformable material such as polyvinyl chloride or polystyrene having a plurality of flexible bubbles or blisters preformed therein and projecting outwardly from one surface to define separate compartments for individual doses of medicine, typically a single pill, and a second lidding or cover sheet of rupturable material such as aluminum foil or paper bonded to the first sheet and overlying and covering the open bubbles. While such packages have provided efficient and effective packaging of individual dosages of medicament in pill form, such packages are not child proof or child resistant, and present a potential hazard to small children.
To render the typical blister package more child resistant, a number of packages have been devised which include additional features intended to render the package difficult for small children to open while at the same time being user friendly for adults including adults who have suffered some loss of manual dexterity.
U.S. Pat. No. 5,310,060 discloses a tamper evident, child resistant blister package in which a non-rupturable film layer is laminated to the outer surface of the rupturable foil lidding sheet, and an external cover sheet of paper or printable film is laminated to the non-rupturable film. A pattern of perforations is formed in and extends through the complete packages along the sides of the individual blisters to enable the user to press a tear tab from the package adjacent a blister. Scores and detents are provided in the package and the blister sheet, respectively, whereby as the pull tabs are lifted, the portion of the rupturable lidding sheet which covers a blister is separated from the pull tab in the area extending over the blister. Thereafter, the user can press on the blister to expel the pill through the rupturable sheet.
U.S. Pat. No. 5,758,774 discloses a blister package for pills in which a paperboard or other backing is provided over the rupturable lidding sheet, and individual scores are provided to enable peeling the backing sheet from the area of an individual blister to enable the pill to be expelled through the exposed rupturable sheet. Alternatively, the child resistant feature may be eliminated by removing the paper board backing from the area of the blister packages over the entire package.
Other child resistant blister packages may be found in U.S. Pat. Nos. 4,125,190; 4,506,789; 5,172,812; 5,323,907; 5,437,371; 5,529,188; 5,775,505; 5,785,180; 5,878,887; 5,927,500; and 5,915,559.
While the known child resistant blister packages have been effective, at least to some degree, in preventing access to the packaged medicament by young children, they have not been entirely satisfactory for a number of reasons. For example, some of the packages, while being child resistant initially, do not retain the desired degree of child resistance after a portion of the product has been dispensed. Also, product packages in some of the child resistant packages have not been as readily accessible to adults as desired, particularly those with loss of manual dexterity. Further, some of the known packages have been relatively expensive to manufacture and or assemble. Accordingly, it is a primarily object of the present invention to provide an improved, inexpensive, child resistant blister packages for medicaments.
Another object is to provide such a blister packages that retains its child resistant feature intact after each dosage use.